Readers of The Sum can now take part in the biggest-ever study of Murphy's Law - "If something can go wrong, it will". Performed by thousands of students across the country, experiments unveiled in this issue of The Sum should finally reveal the truth behind the most notorious version of the law: "If toast can land butter-side down, it will do".

Readers of The Sum have finally proved that Murphy's Law of Toast is true: If it can land butter-side down, it will do !

For years scientists have dismissed the Law as just an urban myth. But in the world's biggest-ever study of Murphy's Law, schoolchildren from across the UK decided to find out for themselves - with spectacularly convincing results.

In the nationwide experiment, toast tumbled off plates a grand total of almost 10,000 times. And the result was conclusive: the toast landed butter-side down 62 per cent of the time, much more often than the 50:50 split predicted by sceptical scientists - and demonstrating the reality of Murphy's Law of Toast once and for all.

Those taking part in the pioneering experiment, devised by Aston University physicist Robert Matthews - the world's leading authority on Murphy's Law - and sponsored by butter-makers Lurpak, did more than just demonstrate that toast does tend to land butter-side down. In the grand tradition of science, they probed the causes too - with intriguing results.

Many think that Murphy's Law of Toast holds true because of the extra weight of the butter on one side. To find out, those taking part carried out a second investigation. This time, the toast was plain - apart from a letter "B" written on one side where the butter would have been. If butter really was to blame, then unbuttered toast should now land "B" side down just as often as "B" side up.

Once again, however, mere opinion has been demolished by the cold, hard reality of experimental evidence. Out of almost 10,000 tumbles, the unbuttered toast still landed "B" side down 58 per cent of the time - just 4 per cent less often than with butter, and still much more often than the 50:50 split expected by chance.

So what is the true cause of Murphy's Law of Toast ? After reporting their results to The Sum's special Murphy's Law website, many pupils commented that they suspected that the height of the plate had something to do with it. As the toast slid of the plate, it began to tumble to the floor - and many thought the toast just didn't have enough time to come butter-side up again by the time it hit the floor.

The truth was revealed in the third and final investigation - this time carried out only by secondary school students. They dropped toast from heights of 2.5 metres; that's much higher than most people carry their toast to the table - but enough to test the idea that toast can land butter-side up if it falls far enough.

Again, the results were conclusive. Out of over 2,000 tumbles from 2.5 metres up, only 47 per cent ended butter-side down - far less than the 62 per cent rate found when toast fell from waist-height, and significantly less even than the 50:50 split expected by chance.

"Thanks to all the hard work of those who took part, the results are conclusive: Murphy's Law of Toast really is true", says Robert Matthews. "A lot of scientists have dismissed it as a silly urban myth, saying that people just forget when toast lands butter-side up. What The Sum and its readers have shown is that you don't have to take an expert's word for anything - you can find out for yourself, and maybe discover that the experts are wrong !".

According to Robert, many pupils did more than just carry out the basic experiments - they also came up with ways of beating Murphy's Law - and tested them out.

"To my mind, the best suggestion was 'butter the other side' - which isn't as silly as it sounds", says Robert. "If you put the toast butter-side down on the plate before setting off for the breakfast table, the butter helps glue to toast to the plate, and if it does slip off, it's got a very good chance of landing butter-side up".